1. Field of the Invention
This invention relates to a method for processing X-ray images with the main object of reconstructing a composite image, at least one dimension of which is appreciably larger than the visualization field of the receiver. By way of example, the receiver employed in this instance can be a luminance amplifier of a type known per se. The invention finds a preferred field of application in angiography, in particular for visualizing at least a large proportion of a patient's blood vessels and circulatory system.
2. Description of the Prior Art
In angiography, it is extremely useful to be able to display on a single document a large part of the arterial and/or venous system such as, in particular, the entire lower arterial and venous system. In the past, examinations of this type have been performed by means of an installation comprising an X-ray source placed at a considerable height above the patient in order to irradiate the entire region to be visualized as well as a film transfer mechanism for taking a series of adjacent photographs corresponding to different portions of this region. This system suffers from the double disadvantage of high operating costs arising from the considerable lengths of photographic film used and also arising from extensive irradiation of the patient. Furthermore, it is not always easy to read the document by reason of the variations in quality of the successive images. More recently, with the appearance of luminance amplifiers which tend to replace films, it has been proposed to take a number of photographs in respect of different relative positions between the source-receiver assembly and the patient-supporting table and to reproduce these photo-graphs in adjacent relation on a single photographic document of distinctly smaller size than the series of photographs described above for an equivalent resolution of the image. Furthermore, the X-radiation dose applied to the patient is reduced to an appreciable extent. However, this type of presentation calls for an effort of mental reconstruction of the image on the part of the physician, which is considered as a restrictive condition.